/**** 
* Plugins
****/ 
var tween = LK.import("@upit/tween.v1");

/**** 
* Classes
****/ 
var Cat = Container.expand(function () {
	var self = Container.call(this);
	var catGraphics = self.attachAsset('cat', {
		anchorX: 0.5,
		anchorY: 1
	});
	var catJumpGraphics = self.attachAsset('cat_jump', {
		anchorX: 0.5,
		anchorY: 1,
		visible: false
	});
	self.isJumping = false;
	self.isDucking = false;
	self.groundY = 2400;
	self.jumpHeight = 200;
	self.normalHeight = 80;
	self.duckHeight = 40;
	self.jump = function () {
		if (!self.isJumping && !self.isDucking) {
			self.isJumping = true;
			LK.getSound('jump').play();
			// Switch to jumping sprite
			catGraphics.visible = false;
			catJumpGraphics.visible = true;
			tween(self, {
				y: self.groundY - self.jumpHeight
			}, {
				duration: 300,
				easing: tween.easeOut,
				onFinish: function onFinish() {
					tween(self, {
						y: self.groundY
					}, {
						duration: 300,
						easing: tween.easeIn,
						onFinish: function onFinish() {
							// Switch back to normal sprite
							catJumpGraphics.visible = false;
							catGraphics.visible = true;
							self.isJumping = false;
						}
					});
				}
			});
		}
	};
	self.duck = function () {
		if (!self.isJumping && !self.isDucking) {
			self.isDucking = true;
			LK.getSound('duck').play();
			catGraphics.height = self.duckHeight;
			LK.setTimeout(function () {
				catGraphics.height = self.normalHeight;
				self.isDucking = false;
			}, 400);
		}
	};
	return self;
});
var Ground = Container.expand(function () {
	var self = Container.call(this);
	var groundGraphics = self.attachAsset('ground', {
		anchorX: 0,
		anchorY: 0
	});
	self.speed = gameSpeed;
	self.update = function () {
		self.x -= self.speed;
		if (self.x <= -self.width) {
			self.x += self.width * groundTiles.length;
		}
	};
	return self;
});
var Obstacle = Container.expand(function (type) {
	var self = Container.call(this);
	self.type = type;
	self.speed = gameSpeed;
	if (type === 'taco') {
		var obstacleGraphics = self.attachAsset('taco', {
			anchorX: 0.5,
			anchorY: 1
		});
		self.y = 2400;
		self.isLow = true;
	} else if (type === 'dinosaur') {
		var obstacleGraphics = self.attachAsset('dinosaur', {
			anchorX: 0.5,
			anchorY: 1
		});
		self.y = 2200;
		self.isLow = false;
	}
	self.update = function () {
		self.x -= self.speed;
	};
	return self;
});

/**** 
* Initialize Game
****/ 
var game = new LK.Game({
	backgroundColor: 0x87ceeb
});

/**** 
* Game Code
****/ 
var gameSpeed = 8;
var obstacleSpawnTimer = 0;
var obstacleSpawnRate = 90;
var minSpawnRate = 30;
var difficultyIncreaseRate = 0.1;
var cat = game.addChild(new Cat());
cat.x = 400;
cat.y = 2400;
var obstacles = [];
var groundTiles = [];
// Create ground tiles
for (var i = 0; i < 15; i++) {
	var groundTile = new Ground();
	groundTile.x = i * 200;
	groundTile.y = 2400;
	groundTiles.push(groundTile);
	game.addChild(groundTile);
}
var scoreTxt = new Text2('0', {
	size: 120,
	fill: 0xFFFFFF
});
scoreTxt.anchor.set(0.5, 0);
LK.gui.top.addChild(scoreTxt);
var distance = 0;
// Play background music
LK.playMusic('background');
function spawnObstacle() {
	var obstacleType = Math.random() < 0.5 ? 'taco' : 'dinosaur';
	var obstacle = new Obstacle(obstacleType);
	obstacle.x = 2200;
	obstacles.push(obstacle);
	game.addChild(obstacle);
}
function checkCollision() {
	for (var i = 0; i < obstacles.length; i++) {
		var obstacle = obstacles[i];
		if (cat.intersects(obstacle)) {
			LK.getSound('collision').play();
			LK.effects.flashScreen(0xff0000, 1000);
			LK.showGameOver();
			return true;
		}
	}
	return false;
}
function handleInput() {
	if (Math.random() < 0.5) {
		cat.jump();
	} else {
		cat.duck();
	}
}
game.down = function (x, y, obj) {
	if (y > 2732 / 2) {
		cat.jump();
	} else {
		cat.duck();
	}
};
game.update = function () {
	distance += gameSpeed;
	var score = Math.floor(distance / 10);
	LK.setScore(score);
	scoreTxt.setText(score);
	// Increase difficulty over time
	if (obstacleSpawnRate > minSpawnRate) {
		obstacleSpawnRate -= difficultyIncreaseRate;
	}
	gameSpeed += 0.002;
	// Spawn obstacles
	obstacleSpawnTimer++;
	if (obstacleSpawnTimer >= obstacleSpawnRate) {
		spawnObstacle();
		obstacleSpawnTimer = 0;
	}
	// Update obstacles
	for (var i = obstacles.length - 1; i >= 0; i--) {
		var obstacle = obstacles[i];
		obstacle.speed = gameSpeed;
		if (obstacle.x < -100) {
			obstacle.destroy();
			obstacles.splice(i, 1);
		}
	}
	// Update ground tiles
	for (var j = 0; j < groundTiles.length; j++) {
		groundTiles[j].speed = gameSpeed;
	}
	// Check for collisions
	checkCollision();
};

===================================================================
--- original.js
+++ change.js
@@ -139,8 +139,10 @@
 });
 scoreTxt.anchor.set(0.5, 0);
 LK.gui.top.addChild(scoreTxt);
 var distance = 0;
+// Play background music
+LK.playMusic('background');
 function spawnObstacle() {
 	var obstacleType = Math.random() < 0.5 ? 'taco' : 'dinosaur';
 	var obstacle = new Obstacle(obstacleType);
 	obstacle.x = 2200;